Improvement in steam-engines



FFICES' JACOB BRADLErfOr sfr. MARYS, Onto.

IMPROVEMENT IN STEAM-ENGINES.

Specification forming part of Letters Patent No. 33,1l, dated September 3. 1861.

To @ZZ whom it may concern.-

Be it known that I, JACOB BRADLEY, ot St. Marys, in the county of Auglaize and State of Ohio, have invented a new and useful Improvement in Steam-Engines; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specication, in which- Figure l is acentral longitudinal and vertical section of the cylinders, valves, and passages of an engine constructed according to my invention. Fig. 2 is a plan of the same with the seat ot the main valve in section in the line @c a', ni'arked in Fig. l. Fig. 3 is a perspective View of the main valve.

Similar letters of reference indicate corresponding parts in the several figures.

This invention relates to that class of steamengines known as high and low pressure steam-engines, in which the steam iirst acts upon a piston in a smaller cylinder and afterward upon a second piston in a larger cylinder.

It consists in an improved valve and system ot ports for effecting the induction and eduction of steam to and from the two cylinders; also in certain means whereby when it is desired to exert great power the full pressure of steam can be made to act upon the larger piston.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and Operation.

A is the smaller and Gthe larger cylinder, arranged end to end, concentric with each other.

B C arethe pistons fitting the said cylinders, both attached to the piston-rod D,which works through a stuffing-box in the partition a between the two cylinders and another stuiiing-box in the outer end of one of the cylinders. The connections of the piston-rod are not represented, as they may be ot any known or suitable kind.

E is the main valve of the engine, ot' the taper plug or cock kind, and F is its seat, consisting of a socket of corresponding taper form arranged transversely to the cylinders near their junction. This seat has at equal distances apart in its circumference five ports, viz: one, s, which is in constant communication with the steam-pipe I-I, which supplies steam from the boiler; two, l) and h', on opposite sides Ot' s, communicating with opposite ends ot the smaller cylinder A, and two, c c', between b and h', communicating with opposite ends ot the larger cylinder G. The smaller end ol' the said socket is open and has connected with it the exhaust-pipe I, leading to the atmosphere or to a condenser. The larger end of the socket is closed by the valveE when the latter is in place. The valve E is hollow and has in its sides a port (l and two cavities e c', the said port (Z com municating with the interior of the valve. To explain the arrangement ot the said port d and cavities e e', I will suppose the circumference of the valve to be divided into eight equal parts. The width of the port (Z is equal to one part, the spaces between that port and the cavities c e on opposite sides of it being each equal to one part, the said cavities being each equal to two parts, andthe space between them being equal to one part. The valve has attached to it an arm f,which is to be connected by a rod g with an eccentric or operated upon by a cam on the crank-shaft of the engine or worked by any other means for the purpose of giving the necessary movement to the valve E-that is to say, a movement back and forth about its axis to the extent of about one-fifth of a revolution, so that the cavity e may bring the port h alternately into communication with the port s, as shown in Fig. l, to give steam to the left-hand end of the smaller cylinder A and into communication with the port c to exhaust t-he steam from that end of the smaller cylinder into the rightfhand end of the larger cylinder G, in which it operates on the piston C by expansion, and that the cavity c may bring the port h alternatelyinto communication with the port s to give steam to the right-hand end ot the smaller cylinder A and into communication with the port c, as shown in Fig. l, to exhaust the steam from that end of the smaller cylinder into the left-hand end ot the larger cylinder G. The same movement ot the valve brings the port d into communication with the ports c and c alternately, and so provides for the exhaust of the steam from the larger cylinder f after it has performed its duty therein. The port e at the lett-hand end of the larger cylinder receives the exhaust-steam from the right-hand end of the smaller cylinder, and

' By the movement ot' the valve E to a position the induction and eduction of the steam to the port c at the right-hand end of the larger cylinder is in communication with the exhaust-pipe I, While the port l) at the lefthand end of the smaller cylinder is receiving fresh steam from the boiler, and the steam acts upon both pistons to produce their movement to the right. This condition is shown in Fig. l.

to open the port b at the right-hand end of the smaller cylinder to the steam in the boiler the ports b and c are brought into communication, and c is opened to the exhaust-pipe I, and the steam acts upon both pistons to produce their movement to the left, and by the movement of the valve being properly timed relatively to the movement of the pistons and the crank or other connection a regular reciprocating movement of the pistons and rotary motion of the main shaft are kept up,

and from both cylinders being entirely controlled by the single valve E.

7c is a pipe connecting the opposite ends of the smaller cylinder A and fitted with a stopcock or stopvalve Z, which is always closed, While the steam is Worked first in the smaller cylinder and then expansively in the larger one, as hereinabove described. The object of this pipe and cock is to provide for the use of the full pressure of steam upon the larger piston C when under any circumstances the exertion of a very great amount of power is desired, and this effect is produced by simply opening the cock or valve Z, which causes the smaller cylinder A to till with and remain full of steam on both sides of its piston B, and the movement of the valve E merely has the effect of admitting steam from A into G at one and the other end of the latter alternately and always opening the opposite end to the exhaust-pipe. In this mode of operation no power is obtained through the piston B, as it continues @in equilibrio. Y

What I claim as my invention, and desire to` secure by Letters Pat-ent, is-

l. The hollo7 valve E,Witl1 its port CZ, and cavities e c', fitted to a seat having ports s Z) b c c', and combined with the steam-pipe H, exhaust-pipe Land the two cylinders A G, substantially as herein specified.

2. Connecting the two ends of the smaller cylinder A by means of a pipe k and stopcock or stop-valve Z, substantially as and for the purpose herein specified.

JACOB BRADLEY.

Witnesses:

JoNA. FAIRBANKS, THOMAS HUssEY. 

